(CNN) Sources on the Senate Intelligence Committee suspect that House Intelligence Chairman Devin Nunes and his staff were behind the leak of Sen. Mark Warner's text messages with a lobbyist for a Russian oligarch.
But Senate Intelligence Committee Chairman Richard Burr denied The New York Times report Thursday that the committee had concluded that the House Intelligence Committee Republicans were involved in the leak of the text messages to Fox News.
Burr said Thursday that he and Warner had met with House Speaker Paul Ryan simply to give him an "update" of their investigation. But a source familiar with the matter said that the two raised concerns about some of Nunes' tactics while meeting with him about their inquiry. Burr and Warner for months have been privately and publicly distancing themselves from Nunes, who has become a polarizing force within the House Intelligence Committee.
The speaker responded that he would not intervene in their dispute with the House Intelligence Committee.
"The speaker heard the senators on their concerns and encouraged them to take them up directly with their counterparts," said Ryan spokeswoman AshLee Strong, who declined to comment further.
Burr categorically denied Thursday that he and Warner raised any concerns with Ryan about Nunes, saying flatly "no" when asked if he did so. And he insisted they did not make any request of Ryan.
"We had no ask of Paul Ryan period," Burr said.
Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, told CNN's Wolf Blitzer that the leak "clearly came from the majority." Schiff said that his committee had received a letter from "private counsel basically setting out much of those facts."
According to a source familiar with the letter, an attorney for the oligarch's lobbyist, Adam Waldman, accused the House Intelligence Republicans of being behind the leak.
A Nunes spokesman and an attorney for Waldman did not respond to a request for comment.
Warner repeatedly declined to comment Thursday on the Times story, saying instead he would not let anyone interfere with the Senate panel's inquiry into Russia meddling.
This is isn't the first time Nunes has played hardball with his foes in the investigation. Last month, CNN reported that he aggressively targeted a witness and an attorney, who accused the chairman and his staff of employing underhanded tactics to embarrass his client.
In this case, congressional sources say the signs point to the House Intelligence Committee being behind the leak of Warner's texts, in which he was trying to arrange a meeting with the author of the dossier on Trump and Russia, Christopher Steele.
One source said that the text messages were provided to the committee in October by the lobbyist ahead of an interview by the committee. When the documents were turned over, Burr and Warner briefed the committee's members about the texts between Waldman and Warner.
After that, the House Intelligence Committee reached out to Waldman requesting the texts between Waldman and Warner, according to the source.
But there was a small difference in the documents he turned over to the House panel — the House texts did not have page numbers stamped on them like the Senate's. Both sets of documents, however, say "CONFIDENTIAL: Produced to USSSSCI on a Confidential basis," a reference to the Senate Intelligence Committee.
After the Fox News story broke last month, with the text messages that lacked page numbers, Waldman's attorney sent the letter to Nunes accusing the committee of leaking the documents, according to the source.
Burr and Republican Florida Sen. Marco Rubio both came to Warner's defense following the Fox report, with Rubio tweeting that Warner had "fully disclosed" the texts to the committee and that it had "zero impact" on the panel's work.